virtio: reset function
A reset function solves three problems:
1) It allows us to renegotiate features, eg. if we want to upgrade a
guest driver without rebooting the guest.
2) It gives us a clean way of shutting down virtqueues: after a reset,
we know that the buffers won't be used by the host, and
3) It helps the guest recover from messed-up drivers.
So we remove the ->shutdown hook, and the only way we now remove
feature bits is via reset.
We leave it to the driver to do the reset before it deletes queues:
the balloon driver, for example, needs to chat to the host in its
remove function.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ec43284..6e0a9fe 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -390,13 +390,14 @@
struct virtnet_info *vi = vdev->priv;
struct sk_buff *skb;
+ /* Stop all the virtqueues. */
+ vdev->config->reset(vdev);
+
/* Free our skbs in send and recv queues, if any. */
- vi->rvq->vq_ops->shutdown(vi->rvq);
while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
kfree_skb(skb);
vi->num--;
}
- vi->svq->vq_ops->shutdown(vi->svq);
while ((skb = __skb_dequeue(&vi->send)) != NULL)
kfree_skb(skb);